Alkylation of aromatic hydrocarbon compounds employing an aluminosilicate zeolite catalyst is known in the art. For instance, U.S. Pat. No. 3,251,897 describes liquid phase alkylation in the presence of aluminosilicates such as faujasite, heulandite, clinoptilolite, mordenite, dachiardite, zeolite X and zeolite Y. Furthermore, U.S. Pat. No. 2,904,607 shows the alkylation of hydrocarbon compounds in the presence of metallic aluminosilicates, e.g., magnesium aluminosilicate. Finally, U.S. Pat. No. 3,751,506 describes a process for the alkylation of aromatic hydrocarbons comprising contacting these hydrocarbons with an alkylating agent in the vapor phase in the presence of a catalyst comprising a crystalline aluminosilicate zeolite.
Unfortunately, while the prior art aluminosilicate catalysts proposed for the alkylation of benzene provide satisfactory yields of desirable products, they have several disadvantages. First, the use of these prior art catalysts in an alkylation reaction results in a large exotherm. Second, substantial amounts of cracking and rearrangement products are formed. Third, multi-substitution is a problem in these prior art processes. Finally, the activity per gram of active catalytic component is very low. Each of these problems is either eliminated or greatly reduced by the use of the instant coated catalyst. Furthermore, since the coated catalyst contains less of the expensive active catalytic material than prior art catalysts, coated catalysts are less expensive per catalyst charge. Thus, the coated catalysts of the invention provide several advantages in the process for alkylating aromatic hydrocarbons which were heretofore lacking in the art.